FIG. 1 (Prior Art) is a diagram of an interactive television receiver unit 100 that is coupled to a server 101 via a packet-switched network such as the Internet 102. "Triggers" 103 are broadcast along with television video 104 so that viewers can view appropriate web content along with television video at appropriate points in the television video.
One example of such an interactive television receiver unit 100 is a WebTV.RTM. Internet Terminal available from WebTV Networks, Inc., of Mountain View, Calif. In the illustrated example, receiver unit 100 includes a television tuner and receiver 106, a modem 107, an audio digital-to-analog converter (DAC) and video encoder 108, and an infrared interface 109. Receiver unit 100 receives triggers 103 and television video 104 via an antenna 110 and the television tuner and receiver 106. Receiver unit 100 is coupled to the Internet 102 via modem 107. Receiver unit 100 is coupled to an ordinary analog television 111 via audio DAC and video encoder 108 and a video link 112 so that receiver unit 100 can use the television screen 113 of television 111 as a display device. A viewer interacts with receiver unit 100 via an infrared remote control unit 134 that is coupled to receiver unit 100 via the infrared interface 109.
A viewer can receive an advertisement for an item and can use receiver unit 100 to order the item as follows. At an appropriate point in the television video, a trigger 103 is broadcast along with the broadcast television video 104. The trigger 103 is received on antenna 110 and causes browser software 114 to display an icon (not shown) on screen 113 along with the television video. The icon queries the user if the user wants to purchase the item. If the viewer selects the icon using the handheld remote control unit 134, then browser 114 uses a Uniform Resource Locator (URL) from the trigger 103 to retrieve an identified order form web page 115. In the illustrated example, the identified.order form web page 115 is retrieved from a merchant's server 101 via the Internet 102.
FIG. 2 (Prior Art) depicts hypertext markup language (HTML) code of web page 115. Web page 115 includes a form area 116 defined by a beginning form tag &lt;FORM&gt; 117 and an ending form tag &lt;/FORM&gt; 118. Within this form area 116, there are four lines 119-122 of HTML code. Browser 114 of receiver unit 100 renders the first line 119 by displaying the text "ORDER FORM" on the screen of the receiver unit. FIG. 3 illustrates the text "ORDER FORM" 123 displayed on the viewer's screen 113.
Browser 114 renders the second line 120 by displaying the text "NAME:" 124 on screen 113 and records information entered by the user in a designed space 125 on screen 113. Similarly, browser 114 renders the third line 121 by displaying the text "CREDIT CARD:" 126 on screen 113 and records information entered by the user in a designated space 127 on screen 113. Browser 114 renders the fourth line 122 by displaying a "SUBMIT" button 128 on screen 113. When the viewer selects the submit button 128 using the handheld remote control unit 134, browser 114 sends the recorded information from spaces 125 and 127 to a destination identified by a URL 129 of the form tag 117.
In the illustrated example, URL 129 identifies a particular file on server 101 that contains a Common Gateway Interface (CGI) program 130 and a database 131. CGI program 130 can be written in any one of a number of suitable languages including C++ and scripting languages. The name and credit card information from fields 125 and 127 is sent in the form of an HTTP request 132 from receiver unit 100 to the CGI program 130. When HTTP request 132 is received, server 101 sends an HTTP response 133 having an HTTP status code back to receiver unit 100. If HTTP request 132 was properly received, then CGI program 130 writes the name and credit card information into data base 131 and sends a "110 OK" status code back to the receiver unit 100 indicating that the request was received properly. The merchant who sells the item can then access data base 131, identify the order to be filled, and fill the order.
The use of such a broadcast trigger may, however, lead to problems. Triggers broadcast along with television video are typically received by a great many receiver units all at roughly the same time. As a result, many receiver units may attempt to access the same web page and order form resources at the same time. Throughput bottlenecks and overloading at the server may result. Accordingly, many potential customers may not be able to access the order form during the overloading period, thereby preventing the ordering of the item, and leading to lost sales. A solution is desired.